good morning all 

im having a bit of trouble with my 2.5 auto x type,on a morning when i start the car it idles rough when cold but when it gets up to normal temp the car is runs fine,but the brake pedal goes hard from time to time indicating i may have a vacuum leak somewhere on the system,now i have changed the 2 timing valve o rings on the inlet manifold,the brake booster pipe,and the other inlet vacuum pipe,now i have put my code reader on the car to see what codes it was giving and it shows P0037 code H02S heater control circuit low bank 1 sensor 2, i know it's telling me that it's the o2 sensor after the cat,but after i have changed all the usual vacuum leak suspects the car still runs rough on idle and i'm still getting a hard brake pedal.would the o2 sensor after the give me the hard brake pedal??? i'm guessing not or have i missed or overlooked something any help would be fantastic so i can get this big cat purring again.

thank you 

Im recieving the same code.did you fix your problem